The objective of this study was to eliminate intersymbol interference (ISI) and echo cancellation in telephone channels by the use of adaptive structures. The adaptive structures employed here included decision feedback equalizers with elimination of intersymbol interference (ISI-DFE), decision feedback equalizers with noise predictor (NP-DFE), hybrid decision feedback equalizers (H-DFE) and echo cancellers, which were adapted independently or conjointly. By means of simulation, the performances of each of the development structures were compared, showing that adapted structures working conjointly presented fewer problems for convergence than when the structures were adapted independently. Based on the preceding results, we conclude that hybrid decision feedback equalizers (H-DFE) conjointly adapted with an echo canceller was the better option for the elimination of intersymbol interference and echo cancellation for high speed data transmission over telephone channels.